Troubleshooting
Sourdough Splitting or Bursting at the Bottom: Causes and Fixes
When a loaf blows out the side or bottom instead of the score, it's an underproofing or scoring problem. Here's the fix.
When sourdough splits or bursts at the bottom or side instead of opening at the score, the loaf was underproofed or the scoring was too shallow — the expanding gas found the weakest point instead of your cut. Fix it with a fuller proof, a deeper and more decisive score, and proper steam.
Why it bursts in the wrong place
During oven spring, gas rapidly expands and will escape somewhere. If you give it a clean, deliberate exit (the score), it opens there. If not, it blows out a random weak spot — often the base or side.
| Cause | Fix |
|---|---|
| Score too shallow | Cut deeper, ~0.5cm at an angle |
| Underproofed | Extend final proof |
| No score at all | Always score lean loaves |
| Uneven shaping | Build even tension |
| Too little steam | Add steam for first 20 min |
Fix 1: Score deeper and at an angle
A timid, shallow score won't direct the spring. Hold the blade at about a 30° angle and make one confident cut about 0.5cm deep. The angled cut creates a flap (the "ear") that lifts as the loaf expands.
Fix 2: Proof a little more
Underproofed dough has lots of pent-up gas and aggressive spring, which is more likely to burst out. A properly proofed loaf springs in a controlled way through the score. Use the poke test.
Fix 3: Steam
Steam keeps the crust soft and extensible during the first 15–20 minutes so the loaf can expand through the score rather than cracking a set crust elsewhere. Use a Dutch oven or add steam to your oven.
Frequently asked questions
Why does it split on the side, not the top?
Either the score was off-center/too shallow, or one side had weaker tension. Score the top center deliberately and shape evenly.
Can over-flouring cause bottom blowouts?
Indirectly — dry seams from too much bench flour can become weak points. Shape with minimal flour.
Should I score more than once?
A single decisive score is enough for most boules and batards. Decorative scoring is fine as long as one cut is deep enough to direct the spring.
A controlled bloom at the score is the reward for the right proof plus a confident cut. SourdoughAI helps time your proof so oven spring goes where you want it.